642 



SCIENCE 



[N. S. Vol. XXXI. No. I 



capable of demonstration may be grouped 

 in a general way as (1) biological relation- 

 ships, (2) morphological and physiological 

 features, (3) economic applications, (4) 

 geographical distribution, (5) esthetic and 

 landscape features. Practical considera- 

 tions enter largely into groupings of any 

 kind. 



1. Biological Relationships. — In this in- 

 stallation it is sought to illustrate species 

 of the various plant families in juxtaposi- 

 tion, the groups thus formed being located 

 in relation to each other in some prede- 

 termined sequence; this sequence in re- 

 cently planted botanical gardens is usually 

 one which seeks to demonstrate not alone 

 affinity, but the progressive increase in 

 floral complexity, in other words, an evolu- 

 tionary sequence. In such installations 

 practical considerations render the se- 

 quence necessarily incomplete in any one 

 set of plantations; sunshine-requiring her- 

 baceous plants and shrubs can not be suc- 

 cessfully grown close to trees, and some 

 natural families, such as Papilionaee£e and 

 Rubiacete contain herbs, shrubs and trees; 

 climatic considerations prevent many fam- 

 ilies being brought into any one sequence; 

 the biological grouping must then be ob- 

 tained piecemeal ; the most satisfactory and 

 least expensive method is to grow the col- 

 lections of trees (arboretum), of shrubs 

 (fruticetum), of vines (viticetum), and of 

 herbaceous plants, for the most part, at 

 least, in separate areas ; families principally 

 composed of plants inhabiting climates 

 other than that of the locality require arti- 

 ficial environment, such as glass houses for 

 tropical and warm-temperate zone plants 

 in gardens of the cold-temperate zone; it 

 would be an interesting experiment to 

 ascertain if arctic plants could be grown 

 successfully in the temperate zones by some 

 system of refrigeration. By a suitable 

 arrangement of land and water, aquatic 



plants may be brought to some extent into 

 juxtaposition with those of the same or 

 related families requiring dry soil. One 

 advantage in the biological grouping of 

 large collections is the facility with which 

 any species represented may be found when 

 wanted. By the formation of a museum 

 of prepared plants, of fruits, seeds and 

 other organs, of photographs and drawings, 

 the biological sequence adopted may be 

 quite completely illustrated. 



By indicating on the labels the native 

 regions of plants biologically grouped, 

 much simple information bearing on geo- 

 graphic distribution may be given. Casual 

 observers are often as much interested to 

 learn where a plant came from as to learn 

 if it has any useful or ornamental features ; 

 the biological grouping also teaches them, 

 by suggestion, that plants even from remote 

 regions are related to other plants which 

 they may know something about, and thus 

 opens up new lines of thought for many 

 people. 



2. Morphological and Physiological Fea- 

 tures.— The demonstration and illustration 

 of structure and function presupposes some 

 acquaintance with elementary botany, which 

 the great majority of visitors do not at 

 present have. The rapid development of 

 nature-study in schools will render group- 

 ings of plants, arranged from these stand- 

 points, much more generally significant 

 than they are at present. It is possible and 

 practicable to form groups of plants se- 

 lected to illustrate the gross morphology 

 and the simpler phenomena of physiology. 

 These groups are more likely to be elabo- 

 rated in gardens established primarily for 

 students than in those laid out primarily 

 for the use of the public. To a certain 

 extent groupings illustrating ecological 

 considerations can also be established with 

 advantage, although areas remaining in the 

 natural state are more useful. 



